Synthetic skin and tissue model

ABSTRACT

A synthetic tissue model using one or more semi-flexible polymers or resin with at least one embedded mesh material is provided herein. The model provides suitable simulation of animal tissue designed to mimic tissue stiffness through varying the polymerization to simulate tissue stiffness level. Multiple polymers or multiple layers of polymer possessing different polymerization levels can be used to simulate tissues with different layers, such as skin. A mesh incorporated in the model provides durability, and can simulate layers of tissue through selection of the mesh material. A skin model using silicone-like material with a nylon tulle mesh was used to simulate skin for surgical procedures. The nylon tulle mesh increased resistance to tearing over time, due to insertion of surgical tools, thereby increasing usable life of the model and enhancing training as the model simulated skin for longer periods of time.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/031,595, entitled “Synthetic Skin and Tissue Model”, filed onJul. 31, 2014, the contents of which are herein incorporated byreference

FIELD OF INVENTION

This invention relates to animal tissue models. More specifically, thepresent invention provides a synthetic model for simulating variousanimal tissues.

BACKGROUND OF THE INVENTION

The need for anatomic models for medicinal science has been presentsince the advent of medicine, when Herophilus first used cadavers totrain individuals. Currently, fresh, frozen, and fixed animal and/orhuman cadaveric tissues are used to educate and train individuals inanatomy and the medicinal sciences. However, these tissues may beanatomically different or possess differing mechanical properties to aliving human patient.

Human skin is often categorized into thick skin, with a thickness of400-600 μm, and thin skin, with a thickness of 75-150 μm. It is formedby a dermal layer, i.e. the dermis, formed of a highly vascularizednetwork of collagen, elastin, fibronectin, and fibroblasts, an epidermallayer, of keratinocytes, melanocytes, Langerhans cells, Merkel cells,and a dermal-epidermal junction (basement membrane) between theepidermis and dermis. The skin can possess a stiffness of 185 N/m to 300N/m, depending on area of the skin, hydration levels, age.

Anatomical reproductions and models are replacing cadavers for medicaltraining. The need to practice surgical techniques has becomeincreasingly important in the rapidly changing medical field. Artificialmodels provide advantages relative to cost, storage, reliability andshelf life. Furthermore, newer models account for differences in softand hard tissue, allowing medical personnel to practice techniques usingenhanced fidelity, and permits medical personnel to examine medicalprocedures and products, and how those procedures and products interactwith a patient.

However, the majority of models will, at most, simulate the hard andsoft tissue. However, some tissues, such as skin, possess varyingcharacteristics throughout the various layers of the tissue. This limitsthe usefulness of such models, as the manipulation (i.e., scoring,cutting, moving, clamping, etc.) performed on the model fails torealistically simulate living tissue. Further, many models are notdurable, and must be replaced at a high frequency. For example, Zeeff(U.S. Pat. No. 7,322,826) developed a soft tissue model formed of anylon core material and a polyurethane cladding, which has limitedelasticity due to the nylon core. The core and cladding are optionallyattached as a bone or modeled bone, or configured to simulate a tendon.The model can be dyed for enhanced realism Additionally, current modelsused for practicing surgical techniques, also known as suture pads, aretypically made from silicone or silicone and foam rubber. Suturing thematerial can be challenging as the silicone and foam tears easily uponpulling the sutures tight and through multiple uses. Examples of currentsuture pads include Smooth-on suture pads, such as various siliconeproducts sold under the EcoFlex mark like EcoFlex 00-30 and EcoFlex Gel,silicon, silicon and latex, or silicone and foam models offered by3-Dmed, as well as models from Simulab, Simvivo, Syndaver, Surgireal.Such high model turnover drastically increases the costs of training, aswell as causing inferior training as the model ages through use.

As such, what is needed is a model that can realistically simulate theweight and consistency of soft tissues, while providing a durableproduct to limit the high turnover associated with most current models.

SUMMARY OF THE INVENTION

An animal tissue model is provided, which is formed from a syntheticskin formed from at least one polymer material designed to simulateanimal tissue and at least one layer of mesh disposed within the atleast one polymer material. The model is made from a silicone or rubbermaterial, or material that is similar to silicone or rubber, such assilicone, rubber, silicone-like material, an elastomeric material, orrubber-like material. Some examples include polyacrylate rubber,ethylene-acrylate rubber, polyester urethane, bromo-isobutyleneisoprene, polybutadiene, chloro-isobutylene isoprene, chlorosulphonatedpolyethylene, polychloroprene, epichlorohydrin, ethylene propylene,ethylene propylene diene monomer, polyether urethane, perfluorocarbonrubber, fluoro-silicone, fluorocarbon rubber, hydrogenated nitrilebutadiene, polyisoprene, acrylonitrile butadiene, polyurethane, styrenebutadiene, styrene ethylene butylene styrene copolymer, polysiloxane,vinyl methyl silicone, acrylonitrile butadiene carboxy monomer, styrenebutadiene carboxy monomer, thermoplastic polyether-ester, styrenebutadiene block copolymer, styrene butadiene carboxy block copolymer. Insome instances the material is layered to simulate fascia. Inclusion ofspecific mesh material can further simulate the fascia. In specificembodiments, the material is printed using a 3-dimensional printer.

Optionally, arteries and veins were modeled from actual human arteriesby injecting fresh cadaver arteries with acrylic resin. Alternatively,arteries and veins were constructed in wax using resin cast human modelduplicating dimensions and shape of actual cerebral human veins. Whenthe vein and artery models were placed in the model mold and syntheticskin added, i.e. one or more elastomeric polymer(s), the wax was removedthermically and/or chemically (Fahrig et al., A Three-DimensionalCerebrovascular Flow Phantom, Medical Physics, 1999, 26 (8): 1589-1599;Kerber, et al., B-Flow Dynamics in the Human Carotid Artery: I.Preliminary Observations Using a Transparent Elastic Model, AmericanJournal of Neuroradiology, 1992, 13:173-180) thereby simulating arteriesand veins. In further alternative variations, simulated veins areconstructed by dipping a glass or brass rod in liquid soft plastic. Therods are repetitively dipped in molten plastic, which forms a thin layerabout the rod. Successively dipping the rods thicken the plastic layer.The soft plastic is allowed to cure around the rod, with one end of therod sealed in soft plastic. Once cooled the rods are removed leavingtubular cavities, which are cut to appropriate length. The ends of thetubes are then sealed by application of a plastic patch dipped in moltenplastic.

The polymer material is optionally two different polymer materials,three different polymer materials, or multiple layers of polymermaterial having differing polymerization levels. The polymer isoptionally bonded using a resin or liquid silicone binder.

The at least one layer of mesh is optionally polyamide (nylon),polyvinylchloride, polyvinylidenechloride, polytetrafluoroethylene,metal, or plastic. Nonlimiting examples of metal mesh include titanium,stainless steel, or surgical steel. Nonlimiting examples of plasticsinclude acrylonitrile butadiene styrene (ABS), high impact polystyrene(HIPS), acrylic (PMMA), cellulose acetate, cyclic olefin copolymer(COC), ethylene-vinyl acetate (EVA), ethylene vinyl alcohol (EVOH),polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF),polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE),fluorinated ethylene-propylene (FEP), perfluoroalkoxy polymer (PFA),polyethylenechlorotrifluoroethylene (ECTFE),polyethylenetetrafluoroethylene (ETFE), perfluoropolyether (PCPE),acrylic/PVC polymer, aromatic polyester polymers (liquid crystalpolymer), polyoxymethylene (acetal), polyamide (PA, nylon),polyamide-imide (PAI), polyaryletherketone (PAEK), polybutadiene (PBD),polybutylene (PB), polybutylene terephthalate (PBT), polycaprolactone(PCL), polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate(PET), polycyclohexylene dimethylene terephthalate (PCT), polycarbonate(PC), polyhydroxyalkanoate (PHA), polyketone (PK), polyester,polyethylene (PE), polyetheretherketone (PEEK), polyetherimide (PEI),polyethersulfone (PES), chlorinated polyethylene (CPE), polyimide (PI),polylactic acid (PLA), polymethylpentene (PMP), polyphenylene oxide(PPO), polyphenylene sulfide (PPS), polyphthalamide (PPA), polypropylene(PP), polystyrene (PS), polysulfone (PSU), polytrimethyleneterephthalate (PTT), polyurethane (PU), polyvinyl acetate (PVA),polyvinyl chloride (PVC), polyvinylidene chloride (PVDC),styrene-acrylonitrile (SAN). Preferably the plastic is polyamide (nylon)tulle netting mesh. In specific embodiments the mesh layer is disposed1-2 mm below the upper surface of the at least one polymer material.Nonlimiting examples include 1 mm, 1.1 mm, mm, 1.2 mm, 1.3 mm, 1.4 mm,1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm. Examples of nyloninclude the ε-caprolactam PA6, the polymer of hexamethylenediamine andadipic acid PA66, a combination of PA6 and PA66, and a combination ofhexamethylenediamine and sebacic acid (P6/PA610).

In some variations, the model is designed to simulate skin. Some skinsections have a stiffness of about 185 N/m to about 320 N/m, or 185 N/mto 320 N/m. For example, skin stiffness can be in the range of about 185N/m to about 210 N/m, about 210 N/m to about 255 N/m, about 280 N/m toabout 320 N/m, 185 N/m to 210 N/m, 210 N/m to 255 N/m, 280 N/m to 320N/m or at 185 N/m, 190 N/m, 200 N/m, 210 N/m, 220 N/m, 230 N/m, 240 N/m,250 N/m, 255 N/m, 260 N/m, 270 N/m, 280 N/m, 285 N/m, 290 N/m, 300 N/m,310 N/m, 320 N/m. The synthetic skin has a thickness of about 75 μm toabout 600 μm, or 75 μm to 600 μm. Nonlimiting examples of thicknessesare 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm,140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm,230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm,320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm,410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm, 490 μm,500 μm, 510 μm, 520 μm, 530 μm, 540 μm, 550 μm, 560 μm, 570 μm, 580 μm,590 μm, 600 μm.

In specific variations of the invention, the model is used to simulate avaginal cuff. In such embodiments, the model optionally includesintegrated ligaments for adhesion onto the base providing physicians achallenging model. A custom mold was used to form the model out ofsilicone or rubber. The ligaments are optionally formed from strands ofnylon. A reusable base holds the vaginal cuff. The integrated mesh inthe model allows suturing of the features without ripping out of thesutured area.

A method of manufacturing the animal tissue model is also disclosed. Atleast one layer of mesh is placed into a mold. At least one polymermaterial is mixed with a crosslinking agent or polymerization and addedto the mold. The at least one polymer material is then permitted topolymerize in the mold, thereby embedding the at least one layer of meshwithin the at least one polymer material.

The at least one polymer material is a silicone or rubber material, ormaterial that is similar to silicone or rubber, such as silicone,rubber, silicone-like material, an elastomeric material, or rubber-likematerial. Some examples include polyacrylate rubber, ethylene-acrylaterubber, polyester urethane, bromo-isobutylene isoprene, polybutadiene,chloro-isobutylene isoprene, chlorosulphonated polyethylene,polychloroprene, epichlorohydrin, ethylene propylene, ethylene propylenediene monomer, polyether urethane, perfluorocarbon rubber,fluoro-silicone, fluorocarbon rubber, hydrogenated nitrile butadiene,polyisoprene, acrylonitrile butadiene, polyurethane, styrene butadiene,styrene ethylene butylene styrene copolymer, polysiloxane, vinyl methylsilicone, acrylonitrile butadiene carboxy monomer, styrene butadienecarboxy monomer, thermoplastic polyether-ester, styrene butadiene blockcopolymer, styrene butadiene carboxy block copolymer.

The mesh material can be plastic. Some examples include plastics such aspolyamide, polyvinylchloride, polyvinylidenechloride,polytetrafluoroethylene, metal, or plastic. Nonlimiting examples ofmetal mesh include titanium, stainless steel, or surgical steel.Nonlimiting examples of plastics include acrylonitrile butadienestyrene, high impact polystyrene, acrylic, cellulose acetate, cyclicolefin copolymer, ethylene-vinyl acetate, ethylene vinyl alcohol,polyvinylfluoride, polyvinylidene fluoride, polytetrafluoroethylene,polychlorotrifluoroethylene, fluorinated ethylene-propylene,perfluoroalkoxy polymer, polyethylenechlorotrifluoroethylene,polyethylenetetrafluoroethylene, perfluoropolyether, acrylic/PVCpolymer, polyoxymethylene, polyamide-imide, polyaryletherketone,polybutadiene, polybutylene, polybutylene terephthalate,polycaprolactone, polychlorotrifluoroethylene, polyethyleneterephthalate, polycyclohexylene dimethylene terephthalate,polycarbonate, polyhydroxyalkanoate, polyketone, polyester,polyethylene, polyetheretherketone, polyetherimide, polyethersulfone,chlorinated polyethylene, polyimide, polylactic acid, polymethylpentene,polyphenylene oxide, polyphenylene sulfide, polyphthalamide,polypropylene, polystyrene, polysulfone, polytrimethylene terephthalate,polyurethane, polyvinyl acetate, polyvinyl chloride, polyvinylidenechloride, styrene-acrylonitrile, or a combination thereof. Preferablythe mesh is polyamide (nylon) tulle netting mesh.

In some embodiments, the at least one polymer material is layered tosimulate fascia. For example, multiple polymer materials are provided,such as a second polymer material, and polymerized in a mold. The firstand second polymer material are aligned with the at least one layer ofmesh and a resin or liquid silicone binder applied to the multiplepolymer materials

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference should be made tothe following detailed description, taken in connection with theaccompanying drawings, in which:

FIG. 1 is an illustration of a first embodiment of the invention made ofmesh embedded about 2 mm below the surface of a polymer synthetic skin.

FIG. 2 is an illustration of a second embodiment of the invention madeof mesh embedded between two layers of polymer synthetic skin.

FIG. 3 is an illustration of a third embodiment of the invention made ofa first mesh embedded about 2 mm below the surface of a polymersynthetic skin and a second mesh embedded below the first mesh.

FIG. 4 is an illustration of a fourth embodiment of the invention madeof a first mesh embedded between a first layer of polymer synthetic skinand second layer of polymer synthetic skin, and a second mesh embeddedbetween the second layer of polymer synthetic skin and a third layer ofpolymer synthetic skin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to “a polypeptide” includes a mixture of two or morepolypeptides and the like.

As used herein, “about” means approximately or nearly and in the contextof a numerical value or range set forth means±15% of the numerical.

As used herein “animal” means a multicellular, eukaryotic organismclassified in the kingdom Animalia or Metazoa. The term includes, but isnot limited to, mammals. Non-limiting examples include rodents, aquaticmammals, domestic animals such as dogs and cats, farm animals such assheep, pigs, cows and horses, and humans. Wherein the terms “animal” or“mammal” or their plurals are used, it is contemplated that it alsoapplies to any animals.

As used herein the term “patient” is understood to include an animal,especially a mammal, and more especially a human that is receiving orintended to receive treatment.

As used herein, “substantially” means largely if not wholly that whichis specified but so close that the difference is insignificant, and suchdifferences do not influence the functional properties of the termbeyond the normal tolerances permitted by one of skill in the art. Insome embodiments, “substantially” means that the differences do not varyby more than 10% or less.

As used herein, “upper” and “lower” or “bottom” are referenced based onthe image depicted in FIG. 1. “Upper” is in a direction toward the topof FIG. 1, and “lower” or “bottom” is directed toward the bottom of FIG.1.

Example 1

Skin model 1 is composed of synthetic skin 2 and embedded mesh 6, asseen in FIG. 1. Nylon tulle netting mesh was placed into a mold andsilicone rubber (Smooth-On, Inc.) poured into the mold to for syntheticskin 2. Optionally, the silicone rubber is added in sequential layers tocreate multi-layered slab of various thicknesses of silicone. Embeddedmesh 6 is set distance a from the exterior surface of synthetic skin 2,such as 1-2 mm from the exterior surface. The resulting model of skinhas the representation of fascia at both the outer and inner surfaces ofthe slab due to the mesh layers located 1-2 mm below both surfaces. Thisnovel suture pad combines several layers that mimic closely what onewould find in real skin. The layers are reinforced to tolerate tensionand pulling while suturing and practicing other procedures.

Example 2

Skin model 1 is composed of synthetic skin 2, formed of multiple layersdesignated as synthetic epidermis 3, synthetic dermis 4, and embeddedmesh 6, as seen in FIG. 2. Synthetic epidermis 3 and synthetic dermis 4are silicone rubber or foam having different stiffness. It is known thatthick skin has a thickness of 400-600 μm, whereas thin skin has athickness of 75-150 μm, and skin has a stiffness that varies from 185N/m to 300 N/m, depending on area of the skin, hydration levels, age.The difference in stiffness between synthetic epidermis 3 and syntheticdermis 4 may be formed by altering the degree of polymerization ofsilicone, thereby causing a difference in the elastomeric properties ofthe silicone, or by using a combination of different elastomericmaterials. Synthetic epidermis 3 and synthetic dermis 4 are layered withmesh, thereby simulating organ walls, muscle, and other tissues withappropriate fascia, thickness, and consistency. A resin, or liquidsilicone, is added to synthetic epidermis 3 and synthetic dermis 4 tobond the layers.

Example 3

Skin model 1 is composed of synthetic skin 2 and two or more layers ofembedded mesh 6, as seen in FIG. 3. Silicone rubber or foam is pouredinto a mold to a distance a. Preferably, distance a is approximately 1-2mm. A first layer of embedded mesh 6 a was placed on the silicone rubberor foam and allowed to partially set. Silicone rubber or foam having thesame properties as the originally poured silicone rubber or foam wasadded to a distance b and a second layer of embedded mesh 6 b was placedon the silicone rubber or foam. The silicone rubber or foam was allowedto partially set again, and a final layer of silicone rubber or foamadded to encapsulate second layer of embedded mesh 6 b in synthetic skin2.

Example 4

Skin model 1 is composed of synthetic skin 2, formed of multiple layersdesignated as synthetic epidermis 3, synthetic dermis 4, syntheticadipose layer 5, and two or more layers of embedded mesh 6, as seen inFIG. 4. Silicone rubber or foam is poured into a mold to a distance a.Preferably, distance a is approximately 1-2 mm. A first layer ofembedded mesh 6 a was placed on the silicone rubber or foam and allowedto fully or partially set. Synthetic dermis 4 is formed by pouring alayer of polymer material onto embedded mesh 6 a to a distance b.Synthetic dermis 4 has a different stiffness from synthetic epidermis 3,which can be accomplished using different polymers or altering thedegree of polymerization of the polymer, such as silicone, therebycausing a difference in the elastomeric properties, as described inExample 2. Alternatively, synthetic dermis 4 is formed by pouring alayer of elastomeric polymer material into a mold and adding a resin, orliquid silicone, to synthetic epidermis 3 and synthetic dermis 4 to bondthe layers.

A second layer of embedded mesh 6 b was placed on synthetic dermis 4.Synthetic adipose layer 5 was then added. Synthetic adipose layer 5 maybe poured onto second layer of embedded mesh 6 b and allowed to set.Alternatively, synthetic adipose layer 5 is poured in a mold and bondedto synthetic dermis 4 as described previously. This allows the synthetictissue layers and mesh to simulating organ walls, muscle, and othertissues with appropriate fascia, thickness, and consistency.

Example 5

A vaginal cuff model was created with integrated ligaments for adhesiononto a base and to provide physicians a challenging model. The model wascreated using a mold. designed to simulate the vagina cuff. Silicone orsilicone rubber was poured into the mold as described in Examples 1-4.The embedded mesh was applied as described above. However, the strandsof the mesh extended beyond the edges of the silicone or siliconerubber. The strands were collected and adhered together using a resin orother adhesive to form simulated ligaments. The ligaments were attachedto a reusable base.

The various layers optionally are differing stiffnesses to simulatevarious layers of epidermis and dermis. An optional third layer isincluded to simulate adipose.

In the preceding specification, all documents, acts, or informationdisclosed does not constitute an admission that the document, act, orinformation of any combination thereof was publicly available, known tothe public, part of the general knowledge in the art, or was known to berelevant to solve any problem at the time of priority.

The disclosures of all publications cited above are expresslyincorporated herein by reference, each in its entirety, to the sameextent as if each were incorporated by reference individually.

While there has been described and illustrated specific embodiments of asuture model and method of manufacture, it will be apparent to thoseskilled in the art that variations and modifications are possiblewithout deviating from the broad spirit and principle of the presentinvention. It is also to be understood that the following claims areintended to cover all of the generic and specific features of theinvention herein described, and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

What is claimed is:
 1. An animal tissue model, comprising: a syntheticskin formed from at least two layers of at least one polymer materialdesigned to simulate animal tissue, wherein the polymer material issilicone, rubber, silicone-like material, an elastomeric material, orrubber-like material; a resin or liquid silicone binder positionedbetween the layers of silicone skin; and at least one layer of mesh,wherein the at least one layer of mesh is disposed within the at leastone polymer material at a distance of between 1-2 mm below surface ofthe polymer material; wherein strands of the at least one layer of meshextend beyond the synthetic skin; a resin adhering the strands of themesh to each other to form simulated ligaments; wherein the syntheticskin has a stiffness of 185 N/m to 300 N/m.
 2. The animal tissue modelof claim 1, wherein the at least one polymer material is polyacrylaterubber, ethylene-acrylate rubber, polyester urethane, bromo-isobutyleneisoprene, polybutadiene, chloro-isobutylene isoprene, chlorosulphonatedpolyethylene, polychloroprene, epichlorohydrin, ethylene propylene,ethylene propylene diene monomer, polyether urethane, perfluorocarbonrubber, fluoro-silicone, fluorocarbon rubber, hydrogenated nitrilebutadiene, polyisoprene, acrylonitrile butadiene, polyurethane, styrenebutadiene, styrene ethylene butylene styrene copolymer, polysiloxane,vinyl methyl silicone, acrylonitrile butadiene carboxy monomer, styrenebutadiene carboxy monomer, thermoplastic polyether-ester, styrenebutadiene block copolymer, or styrene butadiene carboxy block copolymer.3. The animal tissue model of claim 1, wherein the at least one layer ofmesh is polyamide, polyvinylchloride, polyvinylidenechloride,polytetrafluoroethylene, metal, or plastic.
 4. The animal tissue modelof claim 3, wherein the metal is titanium, stainless steel, or surgicalsteel.
 5. The animal tissue model of claim 3, wherein the plastic isacrylonitrile butadiene styrene, high impact polystyrene, acrylic,cellulose acetate, cyclic olefin copolymer, ethylene-vinyl acetate,ethylene vinyl alcohol, polyvinylfluoride, polyvinylidene fluoride,polytetrafluoroethylene, polychlorotrifluoroethylene, fluorinatedethylene-propylene, perfluoroalkoxy polymer,polyethylenechlorotrifluoroethylene, polyethylenetetrafluoroethylene,perfluoropolyether, acrylic/PVC polymer, polyoxymethylene,polyamide-imide, polyaryletherketone, polybutadiene, polybutylene,polybutylene terephthalate, polycaprolactone,polychlorotrifluoroethylene, polyethylene terephthalate,polycyclohexylene dimethylene terephthalate, polycarbonate,polyhydroxyalkanoate, polyketone, polyester, polyethylene,polyetheretherketone, polyetherimide, polyethersulfone, chlorinatedpolyethylene, polyimide, polylactic acid, polymethylpentene,polyphenylene oxide, polyphenylene sulfide, polyphthalamide,polypropylene, polystyrene, polysulfone, polytrimethylene terephthalate,polyurethane, polyvinyl acetate, polyvinyl chloride, polyvinylidenechloride, styrene-acrylonitrile, or a combination thereof.
 6. The animaltissue model of claim 5, wherein the plastic is polyamide tulle nettingmesh.
 7. The animal tissue model of claim 1, further comprising aplurality of polymer materials or a polymer material having differingpolymerization levels.
 8. The animal tissue model of claim 7, whereinthe plurality of polymer materials is two different polymer materials orthree different polymer materials.
 9. The animal tissue model of claim1, wherein the synthetic skin further comprises a synthetic epidermislayer and a synthetic dermis layer, wherein the synthetic dermis layeris positioned below the synthetic epidermis layer and where thesynthetic dermis layer has a different stiffness than the syntheticepidermis layer.
 10. The animal tissue model of claim 9, furthercomprising resin or liquid silicone between the synthetic epidermislayer and the synthetic dermis layer to bond the synthetic epidermislayer and the synthetic dermis layer together.